On earth, the setting sun is known for its fiery tints. Meanwhile on Mars, the daily sunset takes on a more tranquil cast. The Curiosity Rover's first color images of a Martian sunset show the sun dropping beneath the horizon of Gale Crater, where the rover has been exploring the otherwise red planet since 2012.
Curiosity captured the four images in this sequence over a span of nearly seven minutes, notes NASA’s Jet Propulsion Laboratory. The blue tint isn't quite what a human would see. The rover’s camera, Mastcam, is actually a bit less sensitive to blue light than human eyes, but the particles in Mars’ atmosphere permit more blue wavelengths than on earth.
As on earth, writes the lab, those colors intensify with the setting sun. “The effect is most pronounced near sunset,” they write, “when light from the sun passes through a longer path in the atmosphere than it does in mid-day.” The result is an unforgettable extraterrestrial spin on a familiar sight. But don’t think the rover is getting lazy (or overly enraptured by its surroundings). In fact, says JPL in a release, the image was taken as part of an attempt to understand how dust is distributed in Mars’ atmosphere.